Merge pull request #1804 from mydidimo/fbx_export_squashed

Initial FBX Export Support, sponsored by MyDidimo.

CREDITS

@@ -157,12 +157,27 @@ Contributed ExportProperties interface
 Contributed X File exporter
 Contributed Step (stp) exporter
 
+- Thomas Iorns (mesilliac)
+Initial FBX Export support
+
 For a more detailed list just check: https://github.com/assimp/assimp/network/members
 
-Patreons:
+
+========
+Patreons
+========
+
+Huge thanks to our Patreons!
+
 - migenius
 - Marcus
 - Cort
 - elect
 - Steffen
 
+
+===================
+Commercial Sponsors
+===================
+
+- MyDidimo (mydidimo.com): Sponsored development of FBX Export support

code/CMakeLists.txt

@@ -522,6 +522,13 @@ ADD_ASSIMP_IMPORTER( FBX
   FBXDeformer.cpp
   FBXBinaryTokenizer.cpp
   FBXDocumentUtil.cpp
+  FBXExporter.h
+  FBXExporter.cpp
+  FBXExportNode.h
+  FBXExportNode.cpp
+  FBXExportProperty.h
+  FBXExportProperty.cpp
+  FBXCommon.h
 )
 
 SET( PostProcessing_SRCS
@@ -641,7 +648,7 @@ ADD_ASSIMP_IMPORTER( X
   XFileExporter.cpp
 )
 
-ADD_ASSIMP_IMPORTER(X3D
+ADD_ASSIMP_IMPORTER( X3D
   X3DExporter.cpp
   X3DExporter.hpp
   X3DImporter.cpp

code/Exporter.cpp

@@ -97,6 +97,8 @@ void ExportSceneGLB2(const char*, IOSystem*, const aiScene*, const ExportPropert
 void ExportSceneAssbin(const char*, IOSystem*, const aiScene*, const ExportProperties*);
 void ExportSceneAssxml(const char*, IOSystem*, const aiScene*, const ExportProperties*);
 void ExportSceneX3D(const char*, IOSystem*, const aiScene*, const ExportProperties*);
+void ExportSceneFBX(const char*, IOSystem*, const aiScene*, const ExportProperties*);
+//void ExportSceneFBXA(const char*, IOSystem*, const aiScene*, const ExportProperties*);
 void ExportScene3MF( const char*, IOSystem*, const aiScene*, const ExportProperties* );
 
 // ------------------------------------------------------------------------------------------------
@@ -169,6 +171,11 @@ Exporter::ExportFormatEntry gExporters[] =
     Exporter::ExportFormatEntry( "x3d", "Extensible 3D", "x3d" , &ExportSceneX3D, 0 ),
 #endif
 
+#ifndef ASSIMP_BUILD_NO_FBX_EXPORTER
+    Exporter::ExportFormatEntry( "fbx", "Autodesk FBX (binary)", "fbx", &ExportSceneFBX, 0 ),
+    //Exporter::ExportFormatEntry( "fbxa", "Autodesk FBX (ascii)", "fbx", &ExportSceneFBXA, 0 ),
+#endif
+
 #ifndef ASSIMP_BUILD_NO_3MF_EXPORTER
     Exporter::ExportFormatEntry( "3mf", "The 3MF-File-Format", "3mf", &ExportScene3MF, 0 )
 #endif

code/FBXCommon.h

@@ -0,0 +1,86 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2018, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file FBXCommon.h
+* Some useful constants and enums for dealing with FBX files.
+*/
+#ifndef AI_FBXCOMMON_H_INC
+#define AI_FBXCOMMON_H_INC
+
+#ifndef ASSIMP_BUILD_NO_FBX_EXPORTER
+
+
+namespace FBX
+{
+    const std::string NULL_RECORD = { // 13 null bytes
+        '\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0'
+    }; // who knows why
+    const std::string SEPARATOR = {'\x00', '\x01'}; // for use inside strings
+    const std::string MAGIC_NODE_TAG = "_$AssimpFbx$"; // from import
+    const int64_t SECOND = 46186158000; // FBX's kTime unit
+
+    // rotation order. We'll probably use EulerXYZ for everything
+    enum RotOrder {
+        RotOrder_EulerXYZ = 0,
+        RotOrder_EulerXZY,
+        RotOrder_EulerYZX,
+        RotOrder_EulerYXZ,
+        RotOrder_EulerZXY,
+        RotOrder_EulerZYX,
+
+        RotOrder_SphericXYZ,
+
+        RotOrder_MAX // end-of-enum sentinel
+    };
+
+    // transformation inheritance method. Most of the time RSrs
+    enum TransformInheritance {
+        TransformInheritance_RrSs = 0,
+        TransformInheritance_RSrs,
+        TransformInheritance_Rrs,
+
+        TransformInheritance_MAX // end-of-enum sentinel
+    };
+}
+
+#endif // ASSIMP_BUILD_NO_FBX_EXPORTER
+
+#endif // AI_FBXCOMMON_H_INC

code/FBXConverter.cpp

@@ -215,8 +215,13 @@ void Converter::ConvertNodes( uint64_t id, aiNode& parent, const aiMatrix4x4& pa
                 // attach geometry
                 ConvertModel( *model, *nodes_chain.back(), new_abs_transform );
 
-                // now link the geometric transform inverse nodes,
+                // check if there will be any child nodes
+                const std::vector<const Connection*>& child_conns
+                    = doc.GetConnectionsByDestinationSequenced( model->ID(), "Model" );
+
+                // if so, link the geometric transform inverse nodes
                 // before we attach any child nodes
+                if (child_conns.size()) {
                     for( aiNode* postnode : post_nodes_chain ) {
                         ai_assert( postnode );
 
@@ -231,8 +236,17 @@ void Converter::ConvertNodes( uint64_t id, aiNode& parent, const aiMatrix4x4& pa
 
                         new_abs_transform *= postnode->mTransformation;
                     }
+                } else {
+                    // free the nodes we allocated as we don't need them
+                    Util::delete_fun<aiNode> deleter;
+                    std::for_each(
+                        post_nodes_chain.begin(),
+                        post_nodes_chain.end(),
+                        deleter
+                    );
+                }
 
-                // attach sub-nodes
+                // attach sub-nodes (if any)
                 ConvertNodes( model->ID(), *last_parent, new_abs_transform );
 
                 if ( doc.Settings().readLights ) {
@@ -259,6 +273,7 @@ void Converter::ConvertNodes( uint64_t id, aiNode& parent, const aiMatrix4x4& pa
         Util::delete_fun<aiNode> deleter;
         std::for_each( nodes.begin(), nodes.end(), deleter );
         std::for_each( nodes_chain.begin(), nodes_chain.end(), deleter );
+        std::for_each( post_nodes_chain.begin(), post_nodes_chain.end(), deleter );
     }
 }
 

code/FBXExportNode.cpp

@@ -0,0 +1,284 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2018, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+#ifndef ASSIMP_BUILD_NO_EXPORT
+#ifndef ASSIMP_BUILD_NO_FBX_EXPORTER
+
+#include "FBXExportNode.h"
+#include "FBXCommon.h"
+
+#include <assimp/StreamWriter.h> // StreamWriterLE
+#include <assimp/ai_assert.h>
+
+#include <string>
+#include <memory> // shared_ptr
+
+// AddP70<type> helpers... there's no usable pattern here,
+// so all are defined as separate functions.
+// Even "animatable" properties are often completely different
+// from the standard (nonanimated) property definition,
+// so they are specified with an 'A' suffix.
+
+void FBX::Node::AddP70int(
+    const std::string& name, int32_t value
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "int", "Integer", "", value);
+    AddChild(n);
+}
+
+void FBX::Node::AddP70bool(
+    const std::string& name, bool value
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "bool", "", "", int32_t(value));
+    AddChild(n);
+}
+
+void FBX::Node::AddP70double(
+    const std::string& name, double value
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "double", "Number", "", value);
+    AddChild(n);
+}
+
+void FBX::Node::AddP70numberA(
+    const std::string& name, double value
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "Number", "", "A", value);
+    AddChild(n);
+}
+
+void FBX::Node::AddP70color(
+    const std::string& name, double r, double g, double b
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "ColorRGB", "Color", "", r, g, b);
+    AddChild(n);
+}
+
+void FBX::Node::AddP70colorA(
+    const std::string& name, double r, double g, double b
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "Color", "", "A", r, g, b);
+    AddChild(n);
+}
+
+void FBX::Node::AddP70vector(
+    const std::string& name, double x, double y, double z
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "Vector3D", "Vector", "", x, y, z);
+    AddChild(n);
+}
+
+void FBX::Node::AddP70vectorA(
+    const std::string& name, double x, double y, double z
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "Vector", "", "A", x, y, z);
+    AddChild(n);
+}
+
+void FBX::Node::AddP70string(
+    const std::string& name, const std::string& value
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "KString", "", "", value);
+    AddChild(n);
+}
+
+void FBX::Node::AddP70enum(
+    const std::string& name, int32_t value
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "enum", "", "", value);
+    AddChild(n);
+}
+
+void FBX::Node::AddP70time(
+    const std::string& name, int64_t value
+) {
+    FBX::Node n("P");
+    n.AddProperties(name, "KTime", "Time", "", value);
+    AddChild(n);
+}
+
+
+// public member functions for writing to binary fbx
+
+void FBX::Node::Dump(std::shared_ptr<Assimp::IOStream> outfile)
+{
+    Assimp::StreamWriterLE outstream(outfile);
+    Dump(outstream);
+}
+
+void FBX::Node::Dump(Assimp::StreamWriterLE &s)
+{
+    // write header section (with placeholders for some things)
+    Begin(s);
+
+    // write properties
+    DumpProperties(s);
+
+    // go back and fill in property related placeholders
+    EndProperties(s, properties.size());
+
+    // write children
+    DumpChildren(s);
+
+    // finish, filling in end offset placeholder
+    End(s, !children.empty());
+}
+
+void FBX::Node::Begin(Assimp::StreamWriterLE &s)
+{
+    // remember start pos so we can come back and write the end pos
+    this->start_pos = s.Tell();
+
+    // placeholders for end pos and property section info
+    s.PutU4(0); // end pos
+    s.PutU4(0); // number of properties
+    s.PutU4(0); // total property section length
+
+    // node name
+    s.PutU1(name.size()); // length of node name
+    s.PutString(name); // node name as raw bytes
+
+    // property data comes after here
+    this->property_start = s.Tell();
+}
+
+void FBX::Node::DumpProperties(Assimp::StreamWriterLE& s)
+{
+    for (auto &p : properties) {
+        p.Dump(s);
+    }
+}
+
+void FBX::Node::DumpChildren(Assimp::StreamWriterLE& s)
+{
+    for (FBX::Node& child : children) {
+        child.Dump(s);
+    }
+}
+
+void FBX::Node::EndProperties(Assimp::StreamWriterLE &s)
+{
+    EndProperties(s, properties.size());
+}
+
+void FBX::Node::EndProperties(
+    Assimp::StreamWriterLE &s,
+    size_t num_properties
+) {
+    if (num_properties == 0) { return; }
+    size_t pos = s.Tell();
+    ai_assert(pos > property_start);
+    size_t property_section_size = pos - property_start;
+    s.Seek(start_pos + 4);
+    s.PutU4(num_properties);
+    s.PutU4(property_section_size);
+    s.Seek(pos);
+}
+
+void FBX::Node::End(
+    Assimp::StreamWriterLE &s,
+    bool has_children
+) {
+    // if there were children, add a null record
+    if (has_children) { s.PutString(FBX::NULL_RECORD); }
+
+    // now go back and write initial pos
+    this->end_pos = s.Tell();
+    s.Seek(start_pos);
+    s.PutU4(end_pos);
+    s.Seek(end_pos);
+}
+
+
+// static member functions
+
+// convenience function to create and write a property node,
+// holding a single property which is an array of values.
+// does not copy the data, so is efficient for large arrays.
+// TODO: optional zip compression!
+void FBX::Node::WritePropertyNode(
+    const std::string& name,
+    const std::vector<double>& v,
+    Assimp::StreamWriterLE& s
+){
+    Node node(name);
+    node.Begin(s);
+    s.PutU1('d');
+    s.PutU4(v.size()); // number of elements
+    s.PutU4(0); // no encoding (1 would be zip-compressed)
+    s.PutU4(v.size() * 8); // data size
+    for (auto it = v.begin(); it != v.end(); ++it) { s.PutF8(*it); }
+    node.EndProperties(s, 1);
+    node.End(s, false);
+}
+
+// convenience function to create and write a property node,
+// holding a single property which is an array of values.
+// does not copy the data, so is efficient for large arrays.
+// TODO: optional zip compression!
+void FBX::Node::WritePropertyNode(
+    const std::string& name,
+    const std::vector<int32_t>& v,
+    Assimp::StreamWriterLE& s
+){
+    Node node(name);
+    node.Begin(s);
+    s.PutU1('i');
+    s.PutU4(v.size()); // number of elements
+    s.PutU4(0); // no encoding (1 would be zip-compressed)
+    s.PutU4(v.size() * 4); // data size
+    for (auto it = v.begin(); it != v.end(); ++it) { s.PutI4(*it); }
+    node.EndProperties(s, 1);
+    node.End(s, false);
+}
+
+
+#endif // ASSIMP_BUILD_NO_FBX_EXPORTER
+#endif // ASSIMP_BUILD_NO_EXPORT

code/FBXExportNode.h

@@ -0,0 +1,197 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2018, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file FBXExportNode.h
+* Declares the FBX::Node helper class for fbx export.
+*/
+#ifndef AI_FBXEXPORTNODE_H_INC
+#define AI_FBXEXPORTNODE_H_INC
+
+#ifndef ASSIMP_BUILD_NO_FBX_EXPORTER
+
+#include "FBXExportProperty.h"
+
+#include <assimp/StreamWriter.h> // StreamWriterLE
+
+#include <string>
+#include <vector>
+
+namespace FBX {
+    class Node;
+}
+
+class FBX::Node
+{
+public: // public data members
+    // TODO: accessors
+    std::string name; // node name
+    std::vector<FBX::Property> properties; // node properties
+    std::vector<FBX::Node> children; // child nodes
+
+public: // constructors
+    Node() = default;
+    Node(const std::string& n) : name(n) {}
+    Node(const std::string& n, const FBX::Property &p)
+        : name(n)
+        { properties.push_back(p); }
+    Node(const std::string& n, const std::vector<FBX::Property> &pv)
+        : name(n), properties(pv) {}
+
+public: // functions to add properties or children
+    // add a single property to the node
+    template <typename T>
+    void AddProperty(T value) {
+        properties.emplace_back(value);
+    }
+
+    // convenience function to add multiple properties at once
+    template <typename T, typename... More>
+    void AddProperties(T value, More... more) {
+        properties.emplace_back(value);
+        AddProperties(more...);
+    }
+    void AddProperties() {}
+
+    // add a child node directly
+    void AddChild(const Node& node) { children.push_back(node); }
+
+    // convenience function to add a child node with a single property
+    template <typename... More>
+    void AddChild(
+        const std::string& name,
+        More... more
+    ) {
+        FBX::Node c(name);
+        c.AddProperties(more...);
+        children.push_back(c);
+    }
+
+public: // support specifically for dealing with Properties70 nodes
+
+    // it really is simpler to make these all separate functions.
+    // the versions with 'A' suffixes are for animatable properties.
+    // those often follow a completely different format internally in FBX.
+    void AddP70int(const std::string& name, int32_t value);
+    void AddP70bool(const std::string& name, bool value);
+    void AddP70double(const std::string& name, double value);
+    void AddP70numberA(const std::string& name, double value);
+    void AddP70color(const std::string& name, double r, double g, double b);
+    void AddP70colorA(const std::string& name, double r, double g, double b);
+    void AddP70vector(const std::string& name, double x, double y, double z);
+    void AddP70vectorA(const std::string& name, double x, double y, double z);
+    void AddP70string(const std::string& name, const std::string& value);
+    void AddP70enum(const std::string& name, int32_t value);
+    void AddP70time(const std::string& name, int64_t value);
+
+    // template for custom P70 nodes.
+    // anything that doesn't fit in the above can be created manually.
+    template <typename... More>
+    void AddP70(
+        const std::string& name,
+        const std::string& type,
+        const std::string& type2,
+        const std::string& flags,
+        More... more
+    ) {
+        Node n("P");
+        n.AddProperties(name, type, type2, flags, more...);
+        AddChild(n);
+    }
+
+public: // member functions for writing data to a file or stream
+
+    // write the full node as binary data to the given file or stream
+    void Dump(std::shared_ptr<Assimp::IOStream> outfile);
+    void Dump(Assimp::StreamWriterLE &s);
+
+    // these other functions are for writing data piece by piece.
+    // they must be used carefully.
+    // for usage examples see FBXExporter.cpp.
+    void Begin(Assimp::StreamWriterLE &s);
+    void DumpProperties(Assimp::StreamWriterLE& s);
+    void EndProperties(Assimp::StreamWriterLE &s);
+    void EndProperties(Assimp::StreamWriterLE &s, size_t num_properties);
+    void DumpChildren(Assimp::StreamWriterLE& s);
+    void End(Assimp::StreamWriterLE &s, bool has_children);
+
+private: // data used for binary dumps
+    size_t start_pos; // starting position in stream
+    size_t end_pos; // ending position in stream
+    size_t property_start; // starting position of property section
+
+public: // static member functions
+
+    // convenience function to create a node with a single property,
+    // and write it to the stream.
+    template <typename T>
+    static void WritePropertyNode(
+        const std::string& name,
+        const T value,
+        Assimp::StreamWriterLE& s
+    ) {
+        FBX::Property p(value);
+        FBX::Node node(name, p);
+        node.Dump(s);
+    }
+
+    // convenience function to create and write a property node,
+    // holding a single property which is an array of values.
+    // does not copy the data, so is efficient for large arrays.
+    static void WritePropertyNode(
+        const std::string& name,
+        const std::vector<double>& v,
+        Assimp::StreamWriterLE& s
+    );
+
+    // convenience function to create and write a property node,
+    // holding a single property which is an array of values.
+    // does not copy the data, so is efficient for large arrays.
+    static void WritePropertyNode(
+        const std::string& name,
+        const std::vector<int32_t>& v,
+        Assimp::StreamWriterLE& s
+    );
+};
+
+
+#endif // ASSIMP_BUILD_NO_FBX_EXPORTER
+
+#endif // AI_FBXEXPORTNODE_H_INC

code/FBXExportProperty.cpp

@@ -0,0 +1,201 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2018, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+#ifndef ASSIMP_BUILD_NO_EXPORT
+#ifndef ASSIMP_BUILD_NO_FBX_EXPORTER
+
+#include "FBXExportProperty.h"
+
+#include <assimp/StreamWriter.h> // StreamWriterLE
+#include <assimp/Exceptional.h> // DeadlyExportError
+
+#include <string>
+#include <vector>
+#include <sstream> // stringstream
+
+
+// constructors for single element properties
+
+FBX::Property::Property(bool v)
+    : type('C'), data(1)
+{
+    data = {uint8_t(v)};
+}
+
+FBX::Property::Property(int16_t v) : type('Y'), data(2)
+{
+    uint8_t* d = data.data();
+    (reinterpret_cast<int16_t*>(d))[0] = v;
+}
+
+FBX::Property::Property(int32_t v) : type('I'), data(4)
+{
+    uint8_t* d = data.data();
+    (reinterpret_cast<int32_t*>(d))[0] = v;
+}
+
+FBX::Property::Property(float v) : type('F'), data(4)
+{
+    uint8_t* d = data.data();
+    (reinterpret_cast<float*>(d))[0] = v;
+}
+
+FBX::Property::Property(double v) : type('D'), data(8)
+{
+    uint8_t* d = data.data();
+    (reinterpret_cast<double*>(d))[0] = v;
+}
+
+FBX::Property::Property(int64_t v) : type('L'), data(8)
+{
+    uint8_t* d = data.data();
+    (reinterpret_cast<int64_t*>(d))[0] = v;
+}
+
+
+// constructors for array-type properties
+
+FBX::Property::Property(const char* c, bool raw)
+    : Property(std::string(c), raw)
+{}
+
+// strings can either be saved as "raw" (R) data, or "string" (S) data
+FBX::Property::Property(const std::string& s, bool raw)
+    : type(raw ? 'R' : 'S'), data(s.size())
+{
+    for (size_t i = 0; i < s.size(); ++i) {
+        data[i] = uint8_t(s[i]);
+    }
+}
+
+FBX::Property::Property(const std::vector<uint8_t>& r)
+    : type('R'), data(r)
+{}
+
+FBX::Property::Property(const std::vector<int32_t>& va)
+    : type('i'), data(4*va.size())
+{
+    int32_t* d = reinterpret_cast<int32_t*>(data.data());
+    for (size_t i = 0; i < va.size(); ++i) { d[i] = va[i]; }
+}
+
+FBX::Property::Property(const std::vector<double>& va)
+    : type('d'), data(8*va.size())
+{
+    double* d = reinterpret_cast<double*>(data.data());
+    for (size_t i = 0; i < va.size(); ++i) { d[i] = va[i]; }
+}
+
+FBX::Property::Property(const aiMatrix4x4& vm)
+    : type('d'), data(8*16)
+{
+    double* d = reinterpret_cast<double*>(data.data());
+    for (size_t c = 0; c < 4; ++c) {
+        for (size_t r = 0; r < 4; ++r) {
+            d[4*c+r] = vm[r][c];
+        }
+    }
+}
+
+// public member functions
+
+size_t FBX::Property::size()
+{
+    switch (type) {
+    case 'C': case 'Y': case 'I': case 'F': case 'D': case 'L':
+        return data.size() + 1;
+    case 'S': case 'R':
+        return data.size() + 5;
+    case 'i': case 'd':
+        return data.size() + 13;
+    default:
+        throw DeadlyExportError("Requested size on property of unknown type");
+    }
+}
+
+void FBX::Property::Dump(Assimp::StreamWriterLE &s)
+{
+    s.PutU1(type);
+    uint8_t* d;
+    size_t N;
+    switch (type) {
+    case 'C': s.PutU1(*(reinterpret_cast<uint8_t*>(data.data()))); return;
+    case 'Y': s.PutI2(*(reinterpret_cast<int16_t*>(data.data()))); return;
+    case 'I': s.PutI4(*(reinterpret_cast<int32_t*>(data.data()))); return;
+    case 'F': s.PutF4(*(reinterpret_cast<float*>(data.data()))); return;
+    case 'D': s.PutF8(*(reinterpret_cast<double*>(data.data()))); return;
+    case 'L': s.PutI8(*(reinterpret_cast<int64_t*>(data.data()))); return;
+    case 'S':
+    case 'R':
+        s.PutU4(data.size());
+        for (size_t i = 0; i < data.size(); ++i) { s.PutU1(data[i]); }
+        return;
+    case 'i':
+        N = data.size() / 4;
+        s.PutU4(N); // number of elements
+        s.PutU4(0); // no encoding (1 would be zip-compressed)
+        // TODO: compress if large?
+        s.PutU4(data.size()); // data size
+        d = data.data();
+        for (size_t i = 0; i < N; ++i) {
+            s.PutI4((reinterpret_cast<int32_t*>(d))[i]);
+        }
+        return;
+    case 'd':
+        N = data.size() / 8;
+        s.PutU4(N); // number of elements
+        s.PutU4(0); // no encoding (1 would be zip-compressed)
+        // TODO: compress if large?
+        s.PutU4(data.size()); // data size
+        d = data.data();
+        for (size_t i = 0; i < N; ++i) {
+            s.PutF8((reinterpret_cast<double*>(d))[i]);
+        }
+        return;
+    default:
+        std::stringstream err;
+        err << "Tried to dump property with invalid type '";
+        err << type << "'!";
+        throw DeadlyExportError(err.str());
+    }
+}
+
+#endif // ASSIMP_BUILD_NO_FBX_EXPORTER
+#endif // ASSIMP_BUILD_NO_EXPORT

code/FBXExportProperty.h

@@ -0,0 +1,123 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2018, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file FBXExportProperty.h
+* Declares the FBX::Property helper class for fbx export.
+*/
+#ifndef AI_FBXEXPORTPROPERTY_H_INC
+#define AI_FBXEXPORTPROPERTY_H_INC
+
+#ifndef ASSIMP_BUILD_NO_FBX_EXPORTER
+
+
+#include <assimp/types.h> // aiMatrix4x4
+#include <assimp/StreamWriter.h> // StreamWriterLE
+
+#include <string>
+#include <vector>
+#include <type_traits> // is_void
+
+namespace FBX {
+    class Property;
+}
+
+/** FBX::Property
+ *
+ *  Holds a value of any of FBX's recognized types,
+ *  each represented by a particular one-character code.
+ *  C : 1-byte uint8, usually 0x00 or 0x01 to represent boolean false and true
+ *  Y : 2-byte int16
+ *  I : 4-byte int32
+ *  F : 4-byte float
+ *  D : 8-byte double
+ *  L : 8-byte int64
+ *  i : array of int32
+ *  f : array of float
+ *  d : array of double
+ *  l : array of int64
+ *  b : array of 1-byte booleans (0x00 or 0x01)
+ *  S : string (array of 1-byte char)
+ *  R : raw data (array of bytes)
+ */
+class FBX::Property
+{
+public:
+    // constructors for basic types.
+    // all explicit to avoid accidental typecasting
+    explicit Property(bool v);
+    // TODO: determine if there is actually a byte type,
+    // or if this always means <bool>. 'C' seems to imply <char>,
+    // so possibly the above was intended to represent both.
+    explicit Property(int16_t v);
+    explicit Property(int32_t v);
+    explicit Property(float v);
+    explicit Property(double v);
+    explicit Property(int64_t v);
+    // strings can either be stored as 'R' (raw) or 'S' (string) type
+    explicit Property(const char* c, bool raw=false);
+    explicit Property(const std::string& s, bool raw=false);
+    explicit Property(const std::vector<uint8_t>& r);
+    explicit Property(const std::vector<int32_t>& va);
+    explicit Property(const std::vector<double>& va);
+    explicit Property(const aiMatrix4x4& vm);
+
+    // this will catch any type not defined above,
+    // so that we don't accidentally convert something we don't want.
+    // for example (const char*) --> (bool)... seriously wtf C++
+    template <class T>
+    explicit Property(T v) : type('X') {
+        static_assert(std::is_void<T>::value, "TRIED TO CREATE FBX PROPERTY WITH UNSUPPORTED TYPE, CHECK YOUR PROPERTY INSTANTIATION");
+    } // note: no line wrap so it appears verbatim on the compiler error
+
+    // the size of this property node in a binary file, in bytes
+    size_t size();
+
+    // write this property node as binary data to the given stream
+    void Dump(Assimp::StreamWriterLE &s);
+
+private:
+    char type;
+    std::vector<uint8_t> data;
+};
+
+#endif // ASSIMP_BUILD_NO_FBX_EXPORTER
+
+#endif // AI_FBXEXPORTPROPERTY_H_INC

code/FBXExporter.h

@@ -0,0 +1,146 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2018, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+copyright notice, this list of conditions and the
+following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the
+following disclaimer in the documentation and/or other
+materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+contributors may be used to endorse or promote products
+derived from this software without specific prior
+written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+/** @file FBXExporter.h
+* Declares the exporter class to write a scene to an fbx file
+*/
+#ifndef AI_FBXEXPORTER_H_INC
+#define AI_FBXEXPORTER_H_INC
+
+#ifndef ASSIMP_BUILD_NO_FBX_EXPORTER
+
+#include "FBXExportNode.h" // FBX::Node
+
+#include <assimp/types.h>
+//#include <assimp/material.h>
+#include <assimp/StreamWriter.h> // StreamWriterLE
+#include <assimp/Exceptional.h> // DeadlyExportError
+
+#include <vector>
+#include <map>
+#include <memory> // shared_ptr
+#include <sstream> // stringstream
+
+struct aiScene;
+struct aiNode;
+//struct aiMaterial;
+
+namespace Assimp
+{
+    class IOSystem;
+    class IOStream;
+    class ExportProperties;
+
+    // ---------------------------------------------------------------------
+    /** Helper class to export a given scene to an FBX file. */
+    // ---------------------------------------------------------------------
+    class FBXExporter
+    {
+    public:
+        /// Constructor for a specific scene to export
+        FBXExporter(const aiScene* pScene, const ExportProperties* pProperties);
+
+        // call one of these methods to export
+        void ExportBinary(const char* pFile, IOSystem* pIOSystem);
+        void ExportAscii(const char* pFile, IOSystem* pIOSystem);
+
+    private:
+        bool binary; // whether current export is in binary or ascii format
+        const aiScene* mScene; // the scene to export
+        const ExportProperties* mProperties; // currently unused
+        std::shared_ptr<IOStream> outfile; // file to write to
+
+        std::vector<FBX::Node> connections; // conection storage
+
+        std::vector<int64_t> mesh_uids;
+        std::vector<int64_t> material_uids;
+        std::map<const aiNode*,int64_t> node_uids;
+
+        // this crude unique-ID system is actually fine
+        int64_t last_uid = 999999;
+        int64_t generate_uid() { return ++last_uid; }
+
+        // binary files have a specific header and footer,
+        // in addition to the actual data
+        void WriteBinaryHeader();
+        void WriteBinaryFooter();
+
+        // WriteAllNodes does the actual export.
+        // It just calls all the Write<Section> methods below in order.
+        void WriteAllNodes();
+
+        // Methods to write individual sections.
+        // The order here matches the order inside an FBX file.
+        // Each method corresponds to a top-level FBX section,
+        // except WriteHeader which also includes some binary-only sections
+        // and WriteFooter which is binary data only.
+        void WriteHeaderExtension();
+        // WriteFileId(); // binary-only, included in WriteHeader
+        // WriteCreationTime(); // binary-only, included in WriteHeader
+        // WriteCreator(); // binary-only, included in WriteHeader
+        void WriteGlobalSettings();
+        void WriteDocuments();
+        void WriteReferences();
+        void WriteDefinitions();
+        void WriteObjects();
+        void WriteConnections();
+        // WriteTakes(); // deprecated since at least 2015 (fbx 7.4)
+
+        // helpers
+        void WriteModelNodes(
+            Assimp::StreamWriterLE& s,
+            const aiNode* node,
+            int64_t parent_uid,
+            const std::map<std::string,int64_t>& bone_uids
+        );
+        void WriteModelNodes( // usually don't call this directly
+            StreamWriterLE& s,
+            const aiNode* node,
+            int64_t parent_uid,
+            const std::map<std::string,int64_t>& bone_uids,
+            std::vector<std::pair<std::string,aiVector3D>>& transform_chain
+        );
+    };
+}
+
+#endif // ASSIMP_BUILD_NO_FBX_EXPORTER
+
+#endif // AI_FBXEXPORTER_H_INC